[2] Microsoft Excel 97 でふりがな機能が実装されました。
[1] Phonetic object (Excel) | Microsoft Learn, o365devx, , https://learn.microsoft.com/en-us/office/vba/api/excel.phonetic
In Microsoft Excel 97, this object contained the formatting attributes for any phonetic text in the specified range.
[3] Office 97試用レポート, https://pc.watch.impress.co.jp/docs/article/970428/office97.htm
[4] マイクロソフト、Office 98 Macintosh Editionを夏に出荷, https://pc.watch.impress.co.jp/docs/article/980218/ms.htm